The changes of the BBB to Evans Blue (EB) and horseradish peroxidase (HRP) were studied in epileptic seizures induced by different agents and in acute hypertension. The findings, indicating a great regional variability in distribution of the BBB lesions in relation to a type of epileptogenic agent, suggest that local neurotransmitter contents and receptor sensitivity may be instrumental in BBB changes in addition to purely vascular effect of hypertension.